In conventional practice, secondary alkyl sulfates have been prepared by reaction of olefins or alcohols with sulfuric acid followed by neutralization of the intermediate secondary alkyl sulfuric acid with aqueous base, usually sodium hydroxide. The process is complicated by incomplete reaction of the starting olefin or alcohol and by formation of dialkyl sulfates which saponify during the neutralization step, noted above, to equal molar amounts of secondary alkyl sulfate and secondary alcohol.
Unreacted olefin and secondary alcohol, which can amount to 50% by weight or more of the starting olefin, are generally removed from the secondary alkyl sulfate by a process of extraction with an organic solvent as described in U.S. Pat. No. 4,175,092. The extraction process can be complicated by the formation of undesirable emulsions and gels as well as by the dissolution of some of the extracting solvent in the aqueous secondary alkyl sulfate phase. Extracting solvents frequently have objectionable odors and must be removed from the aqueous surfactant solution, an operation which can be accompanied by severe foaming difficulties. When extraction is complete, the concentration of secondary alkyl sulfate in water is generally in the range of 20-40% by weight (F. Asinger, Mono-Olefins: Chemistry and Technology, 1968, pp. 689-694).
It would therefore be advantageous to have solid secondary alkyl sulfate-containing surfactant compositions which are substantially free of water and unreacted organic matter, thus allowing maximum handling flexibility.
A process for preparing surfactant compositions has been found in which secondary alkyl sulfates derived from olefins and/or alcohols can be generated in a manner such that the secondary alkyl sulfate-containing product is a solid which can be used as a surfactant and/or a detergent composition which is particularly suitable for household applications.